One unclear construction detail caused an entire extra sample.

I recently worked on a clothing prototype where the measurements were mostly correct, but one construction detail was not clearly enough. The sample maker interpreted the seam and finishing differently from what I had in mind. The result looked close at first, but the fit and structure were wrong once the garment was worn. We had to make another sample, use more fabric and trims, and repeat part of the shipping and production process. It cost me an extra sample round and delayed the project by almost two weeks. What bothered me most was that the waste could have been avoided with one clearer note or reference image. Since then, I have started paying much more attention to construction notes, assembly details, and how instructions might be understood by someone who has not seen the original idea.

For people who have worked with manufacturers or sample makers, what small communication mistake caused the most expensive or wasteful prototype problem for you?